In a very candid ‘GMA’ interview, the Disney star reveals there were days when her depression was so bad that she couldn’t get out of bed.

Demi Lovato, 18, hopes to inspire young fans with her emotional story. The actress sat down with ABC’s Robin Robertsand explained for the first time why her battle with an eating disorder led her to cut herself. She says throwing up and then not eating for days was a way to punish herself. But Demi’s darkest hour came when she entered treatment at Timberline Knoll, a residential treatment center in Illinois.

“The period of my life I went through [at Timberline] was really dark and I became very depressed and my only way of really coping with it was through my eating disorder so I stopped eating and that was my way of coping with it,” Demi says. “I can’t really pin point a darkest point for me because over the past few years I’ve had so many. I guess my darkest period was going into treatment for the first 48 hours and not having any communication with the outside world. Not even letting some people know I was in there.”

Demi, who reveals there were some days that “I didn’t want to get out of bed,” goes on to say that she had no clue she would be diagnosed with Bipolar disorder.

“I had no idea I was Bipolar until I went into treatment. I was actually manic a lot of the times I would take on work loads and I would say yes I can do this and this and this,” she says. “I was conquering the world but then I would come crashing down and be more depressed than ever.”

But the actress says she’s found an outlet — knitting!

“Today I’m learning how to cope with issues and cope with urges in healthy ways,” she says. “Like I’ve picked up knitting! Who would have ever thought I knit on a Saturday night watching TV. I totally do … I’m a knitter!”